1. Field of the Invention
The present invention is related to a method of forming a color filter touch sensing substrate, and more particularly, to a method of forming a color filter touch sensing substrate with capacitive touch function and capacitive structures (capacitive elements).
2. Description of the Prior Art
Since portable information products, such as PDAs, mobile phones, notebooks, and tablet PCs have become more and more prevalent in everyday life, touch panels have been broadly applied to these products as an input interface. The touch panel has become one of the most important components in tablet PCs with high requirements, because it integrates the input functions with the output functions in the same interface (display).
The conventional method of fabricating a touch display panel includes forming the touch panel and the display panel individually, then assembling the touch panel and the display panel afterwards. Therefore, the conventional touch display panel usually has problems such as heavy weight, high cost, large size, and low transmittance. To solve the problems mentioned above, the touch function has recently been integrated into the display panel. By touching the display panel to vary the capacitance of the sensing pads in the sensing layer, sensing current signals will be generated to form the display panel with touch function. FIG. 1 shows a schematic diagram of a capacitive touch display panel 10 according to the prior art. As shown in FIG. 1, the capacitive touch display panel 10 includes a color filter substrate (CF substrate) 30, a thin film transistor substrate (TFT substrate) 20 and a liquid crystal layer 40. The liquid crystal layer 40 is disposed between the CF substrate 30 and the TFT substrate 20. The liquid crystal molecules of the liquid crystal layer 40 will twist and rotate due to an electric field so as to alter the polarization direction of light. The TFT substrate 20 faces the CF substrate 30. The TFT substrate 20 includes a glass substrate 24 and an array layer 22. The array layer 22 may include TFT structures, pixel electrodes, scan lines, data lines and other elements for controlling pixels (not shown).
The conventional CF substrate 30 is formed by a double side process, and the CF substrate 30 usually includes a glass substrate 36, a capacitive sensing layer 50, a black matrix 34, a color filter 32, and a common electrode (not shown). According to the conventional method, the formation of the CF substrate 30 includes forming a capacitive sensing layer 50 at the outer side of the glass substrate 36, then the glass substrate 36 is turned to the opposite side to form the black matrix 34, the color filter 32, and the common electrode on the inner side of the glass substrate 36. However, due to the fabricating method of the CF substrate 30, the thickness of the glass substrate 36 cannot be thinned down after the elements are formed on the two sides of the CF substrate 30. Therefore the thickness of the conventional glass substrate 36 is usually greater than 0.5 millimeters. Furthermore, because the capacitive sensing layer 50 is disposed at the outer side of the glass substrate 36, the capacitive sensing layer 50 must be made of structures and materials with the characteristics of high hardness and high stability. In this way, the designing variety of the CF substrate 30 will be limited. Additionally, the touch sensitivity of the capacitive touch display panel 10 needs to be improved to enhance the performance of the capacitive touch display panel 10.